Nobody even knows yet the definition of 6th generation.
Yes and no!
Secondly nobody speaks it up, we were also partner in the F35 program. What happened?
In all partnerships there is always a leader or a captain. How much pull this leader has differs as to how the partnership is designed.
In F35, US always had the main control. All other countries were so called “partners”. US allowed their plane to be shared/sold freely to those so called partner states.
In the case of Typhoon, a more equal share of partnership was designed. Although the program was initiated by UK, other 3 partners were made “equal-say” partners.
What makes a sixth generation plane was discussed here many times;
Adaptive cycle engines
Increased stealthiness
Self repair capabilities
Unmanned flight possibilities with more AI input
Network centric defensive capabilities more advanced than 5th gen
Widespread use of directed energy weapons.
etc etc etc
If we get back to the Tempest situation; The main partner here is UK. The driving force behind the technology are two defence giants : Rolls Royce and BAE Systems. Both these companies were instrumental in the development of the F35 and F35B jets. Also Leonardo UK and MBDA UK have shared interests with Italian and UK governments. Then you have Italy with Leonardo and Avio Aero (a GE company in Italy). Then in Japan with IHI (produces for GE Aviation, Pratt & Whitney, and Rolls-Royce Holdings) and Mitsubishi (partners with Boeing).
Rather than merging with a consortium like that, since it would kill our KAAN project altogether, it could be advantageous to run along side it with a Tempest programme, which could bring to our doorstep many technologies without having to pay for the R&D costs for them. Which in turn can be used for our KAAN project.
As our KAAN is going to be the poor man’s F22, a partnership like that can also open avenues of sales for our KAAN to many western countries.
The important point here is to preserve the indigenousness of our KAAN to allow us to have unhindered autonomy over it.
So in a round about way I sympathise with what you are saying.